Drill coupling tool



Sept. 12, 1967 FlG. 3%

I E. A. ANZALONE DRILL CGUPLING TOOL Filed July 6, .1965- United StatesPatent O 3,341,237 DRILL COUPLING TOOL Emilio A. Anzalone, 181 ParsonsSt., Brighton, Mass. 02135 Filed July 6, 196s, ser. No. 469,535 1 Claim.(Cl. 287-125) ABSTRACT OF THE DISCLOSURE A coupling tool is provided forconnecting the upper end of a string of drill steel to the chuck of apower apparatus which rotates and drives the drill string. The tool ischaracterized by an elongated shank portion between a threaded end anddriving lugs whereby the shock absorbing characteristics of the tool areimproved and the tool may be re-threaded after the original threaded endbecomes worn. Grooves are provided to permit lubricants to circulatearound the threads.

This invention relates generally to drilling equipment and moreparticularly is directed towards -a new and improved coupling tool ofthe sort used to connect drill steel Vto a power driven chuck.

In drilling through such things as earth or rock to any great depth theusual equipment employed includes a power source such as a steam, gas ordiesel engine drivingly connected to a rotary table or chuck to which is-attached a coupling tool. The coupling tool typically is of tubularconstruction having lugs formed therein for locking with the chuck. Theouter end of the tool is threaded for attaching sections of drill steelto the tool to form a string. As the drilling progresses sections of thedrill steel are added to the drill string by drawing the tool and itsstring, disconnecting the tool from the uppermost section of drill steeland reconnecting a new section of drill steel and then again loweringthe string back into the hole. At the lower end of the string there isconnected a drill head which may be of hardened steel or othersuitablecutting material.

In practice the entire string is tubular to permit a flow of .a drillingfluid such as air, water or mud which is a mixture of various clays andchemicals. In any event the fluid is pumped through the drill sectionsto provide cooling and to facilitate the removal of cuttings from thebore hole.

Insofar as the coupling tool serves to transmit power from the enginedriven chuck to the drill string, it is subjected to a good deal ofshock as well as torsional stresses. It will be understood that asdrilling progresses the drill tip may work through from a relativelysoft stratum into a relatively hard stratum producing shocks which willbe transmitted back to the coupling tool. Also because of the heavyWeight of the drill string and the high torque required to rotate thestring, the coupling tool is under heavy torsional forces. For thisreason the coupling tool is subjected to frequent failures whichnecessitate replacement of the coupling tool.

Also, due to the fact that sections of drill steel are being added orremoved from the threaded end of the coupling tool at frequentintervals, the threads are subjected to a good deal of wear. Also,because of the high-torsional strain applied to the drill string, it isusually a difficult job to unscrew the drill steel from the couplingtool.

Accordingly, it is .an object of t-he present invention to provideimprovements in drill coupling tools.

Another object of this invention is to provide a drill coupling tool ofincreased durability and eiciency.

Still another object of this invention is to provide a drill couplingtool in which the threads are lubricated during operation of the drill.

Patented Sept. 12, 1967 ice of radially extending grooves between theaxial passage of the tool and the outer threaded circumference.Longitudinal grooves are also formed in the outer surface of the tool atthe start of the threads. In this fashion the drilling fluid will seepcontinuously in and around the threads providing constant lubrication tolower the wear between the tool and the drill steel and also tofacilitate uncoupling of the members when required.

However, these and other features of the invention, along with furtherobjects and advantages thereof, will become more fully apparent from thefollowing detailed description of a preferred embodiment of theinvention, with reference being made to the accompanying drawings, inwhich:

FIG. 1 is a view in side elevation of a drill coupling tool madeaccording to the invention,

FIG. 2 is an end view thereof,

FIG. 3 is a view in side elevation showing the tool in association withdrilling apparatus, and',

FIG. 4 is a side elevation of a worn tool that has been shortened andrethreaded.

Referring now to the drawings, the reference character 10 generallyindicates a drill coupling tool typically fabricated from high qualityalloy steel having a hardness of about -60 on the Rockwell C scale. Thetool is of tubular construction being formed with an axial passage 12extending lengthwise therethrough as a conduit for drilling fluid whichis circulated through the drill string. In practice, the passage 12,which is more commonly known as the blow hole, has a diameter 4on theorder of 7A@ of an inch in the smaller size tools whereas the largersi'ze tools may have a passage diameter of about M6 of an inch.

The tool body is formed with integral lugs 14 extending radiallyoutWa-rd from the shank of the tool near the upper end thereof as viewedin FIG. 1. These lugs serve to lock the tool to a chuck 16 in order toprevent the tool from rotating in the chuck. Normally only a pair oflugs is required, one on either side of the tool body.

While the tool may be made in various outside diameters ranging from 1"up to 2%, for example, a length of about l7"i is required for optimumperformance.

In the illustrated embodiment the overall length of the tool is 17" iwith the lugs 14 being about 11/2 in length and located about 31/2 fromthe upper end of the tool. The tool is formed with a shank portion 18approximately 81/2" in length. The lower end of the tool is threaded at20 with the threaded portion covering about 31/2" of the length of thetool. The threads may be made up in a variety of selected thread sizesranging from 1-2 x 150 to 1700, for example. In any event, the shankportion 18 is substantially longer than the Shanks of conventional drillcoupling tools. Drill coupling tools presently available are relativelyshort having overall lengths of about 12" with Shanks of about only 3 or4 in length. These relatively short shanks by reason of their inherentstiffness are incapable of standing up under sustained vibration andimpacts developed during usual drilling operations. As a result,coupling tools of this type heretofore have had relatively short livesrequiring frequent replacement. Insofar as these tools are relativelyexpensive by reason of the high quality alloy steels employed in theirmanu- 3 facture, the replacement of the tools becomes a substantial costfactor in drilling operations.

In the present tool, it has been found that elongating the shank toapproximately twice the normal length previously used, the life of thetool may be greatly increased. This increase in length of the toolresults from the improved shock absorbing characteristics of theelongated shank. By increasing the length of the shank the tool isbetter able to absorb torsional as well as axial stresses producedtherein during drilling operations.

An additional advantage in fabricating the tool with an elongated shankportion is that the shank portion may be employed to rethread the toolin the event that the original threads become too worn to be of furtheruse. Assuming that after long and heavy use the threads 20 becomeexcessively worn, the tool may be set up on a lathe for example, and thethreaded portion cut completely off thus shortening the tool. Theremaining shank portion may then be threaded in the same manner as theprevious threads thus providing a tool such as shown in FIG. 4 which maybe reused. This shortening of the tool thus provides a double life notavailable in conventional tools which are too short to be rethreaded inthis manner.

In order to provide lubrication of the couplings and to alleviateexcessive tightening between the tool and sections of drill steelthreaded thereto means have been provided to permit the drilling fluidto flow or seep continuously in and around the threads. As best shown inFIGS. 1 and 2, the tool has been formed with a plurality of groovesbetween the blow hole passage and the outer periphery of the tool at thethreaded end thereof. As shown in FIG. 2, the grooves 22 extend radiallyoutward and are spaced equi-distantly about the tool. ln the illustratedembodiment, three grooves are formed 120 apart. In this fashion, whenthe tool is threaded with its grooved end butt against the end of asection of drill steel radial passages will be formed between the blowhole 12 and the threads. Since a certain amount of clearance existsbetween the threads of the male end of the tool and the threads formedin the female end of the drill steel, the drill fluid will seep out andaround the threads. In order to permit the fluid to discharge out of thethreads longitudinal grooves 24 are formed in the shank at the start ofthe threads. These grooves typically are three in number spaced 120apart and in register with the radial grooves 20.

By forming the grooves 22 and 24, a continuous flow or seepage ofdrilling uid passes in, around and out of the threads thus maintaining acontinuous lubrication which greatly enhances the wearingcharacteristics of the threads and also prevents the tool from becomingengaged too tightly with the drill steel. Thus sections of drill steelmay be added or removed in a much easier fashion than heretofore andwith less wear upon the threads.

It will be appreciated that while the tool described and illustratedherein is of relatively simple construction, it greatly enhances thelife expectancy and efficiency of coupling tools without greatlyincreasing the cost of the same.

While the invention has been described with particular reference to theillustrated embodiment, it will be understood that numerousmodifications thereto will appear to those skilled in the art.Accordingly, the above description and accompanying drawings should betaken as illustrative of the invention and not in a limiting sense.

Having thus described the invention, what I claim and desire to obtainby Letters Patent of the United States is:

A drill coupling, comprising (a) an elongated tubular body of hardenedmetal,

(b) radially extending lugs formed in said body adjacent one endthereof,

(c) threads formed on the opposite end thereof,

(d) said body being formed with an elongated smooth shank portionbetween said lugs and said threads and of substantially the samediameter as the threaded end, said shank portion comprisingapproximately one-half the total length of said body,

(e) said body being radially grooved at the threaded end of said bodybetween the start of said threads and the center of said body and beinglongitudinally grooved along the outer surface of said body between saidshank portion and the end of said threads.

References Cited UNITED STATES PATENTS 484,764 10/1892 Elder 285-13647,953 4/ 1900 Ferriott 287-20.92 X 1,211,080 1/1917 Carter 287-1251,645,802 10/1927 Davis 287-125 1,714,818 5/1929 Reed 287-20.92 X2,569,275 9/1951 Baker 287-125 X 3,153,356 10/1964 Dearborn 287-125 XCARL W. TOMLIN, Primary Examiner.

W. L. SHEDD, Assistant Examiner.

